Paliperidone (Sold as INVEGA, Semap) is an atypical antipsychotic developed by Janssen Pharmaceutica. Invega is an extended release formulation of paliperidone that uses the OROS (Osmotic Release Oral Systems) extended release system to allow for once-daily dosing. Chemically, paliperidone is primary active metabolite of the older antipsychotic risperidone (paliperidone is 9-hydroxyrisperidone, i.e. risperidone with an extra hydroxyl group). While its specific mechanism of action is unknown, it is believed paliperidone and risperidone act via similar, if not the same, pathways.

Paliperidone (as Invega) was approved by the FDA for treatment of schizophrenia on December 20, 2006. This agent will initially be marketed for the treatment of schizophrenia and then for bipolar mania. Clinical trials of paliperidone for the treatment of schizoaffective disorder are also planned.